0.05).Conclusion Cerebral stroke types,courses and lesions sizes,locations have no effetct on the serum level of homocysteine.

In order to find the most suitable algorithm of T-wave end point detection for clinical detection, we tested three methods, which are not just dependent on the threshold value of T-wave end point detection, i. e. wavelet method, cumulative point area method and trapezium area method, in PhysioNet QT database (20 records with 3 569 beats each). We analyzed and compared their detection performance. First, we used the wavelet method to locate the QRS complex and T-wave. Then we divided the T-wave into four morphologies, and we used the three algorithms mentioned above to detect T-wave end point. Finally, we proposed an adaptive selection T-wave end point detection algorithm based on T-wave morphology and tested it with experiments. The results showed that this adaptive selection method had better detection performance than that of the single T-wave end point detection algorithm. The sensitivity, positive predictive value and the average time errors were 98.93%, 99.11% and (--2.33 ± 19.70) ms, respectively. Consequently, it can be concluded that the adaptive selection algorithm based on T-wave morphology improves the efficiency of T-wave end point detection.
Algorithms ; Electrocardiography ; Humans ; Wavelet Analysis

The mechanical model of knee is a system of constructional elements with specific restrains and material properties, which are deduced from the components of knee based on their functions and junctions. Kinematics and kinetics of knee can be calculated from the mechanical model. A review of some mechanical models of knee are shown in this paper.
Biomechanical Phenomena ; Computer Simulation ; Humans ; Knee Joint ; physiology ; Models, Biological ; Range of Motion, Articular ; physiology ; Stress, Mechanical

Resorption and osteolysis of periimplant bones resulting from the wear debris of artificial joint will cause long-term loosening. A new type of rolling knee artificial joint without UHMWPE based on the mechanics of rolling friction is designed for alleviating this problem. Because of low friction force, the resistance of extension and flexion is reduced strikingly and the stress on the interface between prosthesis and bone is reduced evidently. In addition, the bio-toxicity caused by the wear debris of UHMWPE will not occur absolutely. In consequence, the rolling artificial joint can prevent the trend of long-term loosening of the prosthesis efficiently.
Animals ; Arthroplasty, Replacement, Knee ; Ceramics ; chemistry ; Computer-Aided Design ; Dogs ; Humans ; Knee Prosthesis ; Materials Testing ; Polyethylenes ; Prosthesis Design ; Vitallium ; chemistry

A sagittal plane model of knee joint based on crossed-four-bar-linkage-based tibiofemoral joint model has been developed using geometric and force equilibrium constraints. The model predicts and explains the movement of contact point on the patella and femur, variation of patellar and patellar tendon angle, variation of patellar mechanism angle and variation of patellofemoral contact force and patellar tendon force. The computed results agree well with the published experimental results.
Biomechanical Phenomena ; Humans ; Knee Joint ; anatomy & histology ; physiology ; Models, Biological ; Movement ; physiology ; Patella ; anatomy & histology ; physiology

A novel method for the design of hip joint prostheses based on X-ray films is introduced. Only arcs and straight-lines form figures of hip joint prostheses. Because geometrical tolerances of manufacturing hip joint prostheses matching section are usually not strict, hip joint prostheses can be manufactured without CNC machine tool. Three hip joint prostheses for three different femurs were designed through a program which was developed by the present authors. Approximate marrow cavities of these femurs were simulated according to a standard database about femur. These models of femur marrow cavities were used to verify the hip joint prostheses designed. These hip joint prostheses designed were manufactured and implanted into femurs respectively. Experimental results indicate that the novel method for the design of hip joint prostheses is practicable.
Computer-Aided Design ; Hip Joint ; diagnostic imaging ; Hip Prosthesis ; Humans ; Prosthesis Design ; methods ; Tomography, X-Ray Computed

Objective To quantitatively compare the γ-H2AX foci formation between DNA-PKcs+/+and DNA-PKcs-/-mouse embryonic fibroblast(MEF)cells,and to investigate the dynamic changes in DNA double-strand breaks(DSBs)in human nasopharyngeal carcinoma SUNE-1 cells exposed to X-ray radiation. Methods The expression of DNA-PKcs was determined by Western blot. The γ-H2AX foci formation induced by 5 Gy X-ray radiation was detected by cell immunofluorescence. The ImageJ software was used to quantitatively analyze the γ-H2AX foci formation. Results The expression of DNA-PKcs was silenced in DNA-PKcs-/-MEF cells and normal in DNA-PKcs+/+MEF cells. According to the dynamic analyses of the numbers of γ-H2AX foci/cell and γ-H2AX foci/mm2, a similar tendency was observed in DSB formation in DNA-PKcs+/+MEF cells, DNA-PKcs-/-MEF cells,and SUNE-1 cells exposed to X-ray radiation. A large number of γ-H2AX foci formed at 0.5-1.0 h after radiation. DSBs were repaired at 6 h after radiation in DNA-PKcs+/+MEF cells and 24 h after radiation in DNA-PKcs-/-MEF cells and SUNE-1 cells. The peak values of γ-H2AX foci/cell and γ-H2AX foci/mm2were observed at 1.0 and 0.5 h after radiation, respectively. Compared with DNA-PKcs+/+MEF cells, DNA-PKcs-/-MEF cells had different numbers of γ-H2AX foci/cell at 0.5, 1.0, 3.0, 6.0, and 12.0 h after radiation, as well as different numbers of γ-H2AX foci/mm2at 3.0, 6.0, and 12.0 h after radiation. Conclusions Quantitative measurement of the number of γ-H2AX foci/cell or γ-H2AX foci/mm2by cell immunofluorescence provides new insights into the quantitative and dynamic study of DSB damage and repair.